Damping means, in particular for furniture

ABSTRACT

In an item of furniture having a movable furniture part, such as a drawer, door or folding part, there is provided a damping means which damps movement of the movable furniture part in the closing phase of the closing and/or opening movement. The damping means is constructed as a negative-pressure damping means or combined pressurised and negative-pressure damping means. It has a piston ( 3 ) with a resiliently deformable piston part ( 6 ) in the piston rod ( 4 ), this resiliently deformable piston part ( 6 ) being pressed against the cylinder wall during the damping procedure.

[0001] The invention relates to a damping means, in particular forfurniture, having a piston which is linearly displaceable in a cylinderchamber of a cylinder and is provided with a resiliently deformablepiston part which is pressed against the cylinder wall during thedamping procedure.

[0002] The object of the invention is to construct a damping means whichis in particular suitable for damping the movement of furniture partssuch that the damping action increases to its maximum value very rapidlyin relation to the piston travel.

[0003] The object according to the invention is achieved in that theresiliently deformable piston part is constructed on a piston rod, whichis constructed on the piston and is guided in a channel in the cylinderwhich has a smaller diameter than the piston, with the resilientlydeformable piston part widening radially under axial compressive loadand abutting against the wall of the channel.

[0004] Advantageously, it is provided for a negative pressure to beformed in the cylinder during the damping procedure, between the pistonand the resiliently deformable piston part.

[0005] So that the piston does not become stationary when the negativepressure and the friction on the one hand and the counteracting force onthe pressure side of the piston are of the same size, in an exampleembodiment of the invention the piston is provided with at least onenozzle.

[0006] In a further example embodiment of the invention, there isprovided in the cylinder wall an axial depression which forms anoverflow point from a front chamber part to a rear chamber part when thepiston is located in the region of the depression. Furthermore, it wouldbe possible to guide the piston in the cylinder chamber with a certainamount of play, so that a constant overflow from one chamber part to theother is ensured. It goes without saying that the play must be smallenough not to prevent a negative pressure from being formed.

[0007] Various example embodiments of the invention will be describedbelow with reference to the figures in the attached drawings, in which:

[0008]FIG. 1 shows a longitudinal section through a damping meansaccording to the invention, in which the piston is shown in the startingposition or ready position,

[0009]FIG. 2 shows a longitudinal section through a damping meansaccording to the invention, in which the piston is shown in the dampingposition,

[0010]FIG. 3 shows a longitudinal section through a damping meansaccording to the invention, in which the piston is shown in the endposition,

[0011]FIG. 4 shows a longitudinal section through a further exampleembodiment of a damping means according to the invention, in which thepiston is shown in the starting position or ready position,

[0012]FIG. 5 shows a longitudinal section through a further exampleembodiment of a damping means according to the invention, in the readyposition,

[0013]FIG. 6 shows the detail A from FIG. 5,

[0014]FIG. 7 shows, diagrammatically and in partial section, the pistonof the damping means,

[0015]FIG. 8 shows a longitudinal section through a damping meansaccording to FIG. 5 at the start of the damping movement,

[0016]FIG. 9 shows the detail A from FIG. 8,

[0017]FIG. 10 shows a section along the line l-l in FIG. 8, and

[0018]FIG. 11 shows a longitudinal section through a further exampleembodiment of a damping means in the ready position,

[0019]FIG. 12 shows a longitudinal section through a further exampleembodiment of a damping means according to the invention, in which thepiston is shown in the starting position or ready position,

[0020]FIG. 13 shows a longitudinal section through a damping meansaccording to the invention, in which the piston is shown in the dampingposition,

[0021]FIG. 14 shows the detail A of FIG. 12,

[0022]FIG. 15 shows the detail B of FIG. 13,

[0023]FIG. 16 shows a longitudinal section through a further exampleembodiment of a damping means according to the invention, in which thepiston is shown in the starting position or ready position,

[0024]FIG. 17 shows a longitudinal section through a damping meansaccording to the invention, in which the piston is shown in the dampingposition,

[0025]FIG. 18 shows the detail A of FIG. 16,

[0026]FIG. 19 shows the detail B of FIG. 17,

[0027]FIG. 20 shows a longitudinal section through a further exampleembodiment of a damping means according to the invention, in which thepiston is shown in the starting position or ready position,

[0028]FIG. 21 shows a longitudinal section through a damping meansaccording to the invention, in which the piston is shown in the dampingposition,

[0029]FIG. 22 shows the detail A of FIG. 20,

[0030]FIG. 23 shows the detail B of FIG. 21,

[0031]FIG. 24 is a section along line C-C of FIG. 20,

[0032]FIG. 25 shows a longitudinal section through a further exampleembodiment of a damping means according to the invention, in which thepiston is shown in the starting position or ready position,

[0033]FIG. 26 shows a longitudinal section through a damping meansaccording to the invention, in which the piston is shown in the dampingposition,

[0034]FIG. 27 shows the detail A of FIG. 25,

[0035]FIG. 28 shows the detail B of FIG. 26,

[0036]FIG. 29 is a section along line C-C of FIG. 25,

[0037]FIG. 30 shows a longitudinal section through a further exampleembodiment of a damping means according to the invention, in which thepiston is shown in the starting position or ready position,

[0038]FIG. 31 shows a longitudinal section through a damping meansaccording to the invention, in which the piston is shown in the dampingposition,

[0039]FIG. 32 shows the detail A of FIG. 30,

[0040]FIG. 33 shows the detail B of FIG. 31.

[0041] The damping means according to the invention has a cylinder 1with a cylinder chamber 2 in which a piston 3 is linearly movable. Thepiston 3 divides the cylinder chamber 2 into a rear chamber part 2′ anda front chamber part 2″.

[0042] Constructed on the piston 3 is a piston rod 4 which projectsthrough a channel 5 in the cylinder 1 and is part of the piston 3. Thepiston rod 4 is received in the channel 5 with play, with the resultthat the piston rod 4 and the channel wall 9 delimit an annular gap 10in the rest position of the piston 3.

[0043] The piston 3 is guided in the cylinder chamber 2 in sealingmanner.

[0044] The piston rod 4 comprises two rigid portions 7, 8 between whicha resiliently deformable piston part 6 is arranged. The piston part 6 isconstructed as a solid body from material with a rubber-like resilience.

[0045] At its free end, the piston rod 4 is provided with a buffer 11 ofresilient material and, furthermore, with a covering cap 12 which hastwo air vents 13. The covering cap 12 is guided in an annular gap 14 inthe cylinder 1, and a compression spring 15 is arranged within thecovering cap 12 and moves the piston 3 into the starting position viathe piston rod 4. The cylinder 1 has an air through opening 17 in itsend face, through which air can flow into and out of the chamber part2″.

[0046] During damping, the furniture part, for example a door or adrawer, strikes against the buffer 11 of the piston rod 4 and pressesthe latter, together with the piston 3, to the right (in relation to thefigures in the drawing). As soon as the piston 3 moves, a negativepressure is produced behind the piston 3 in the rear chamber part 2′ ofthe cylinder chamber 2, even though air flows in through the throughopenings 13 and the annular gap 10 between the piston rod 4 and the wall9 of the channel 5 into the chamber part 2′. Because the annular gap 10is kept very narrow, the supply of air is very small.

[0047] With a slow piston movement, enough air flows in and the piston 3continues to move unimpeded.

[0048] With a relatively fast piston movement, too little air flowsthrough the annular gap 10 into the chamber part 2′, and a negativepressure is produced behind the piston 3. This negative pressuregenerates a force F1 which counteracts the piston movement.

[0049] This has the effect that the resiliently deformable piston part 6in the piston rod 4 is compressed, whereupon this piston part 6 expandsradially, as shown in FIG. 2, and is pressed against the wall 9 of thechannel 5. This means the annular gap 10 is closed and further movementof the piston 3 is impeded both by the negative pressure in the chamberpart 2′ and by the friction between the middle piston part 6 and thewall 9.

[0050] If a force continues to act on the piston 3 in the direction ofthe arrow F2 in FIG. 2, the piston 3 may remain stationary, if acounteracting force F1 of the same size has built up as a result of thenegative pressure and the friction.

[0051] In order to prevent the piston 3 remaining stuck in the middle ofthe cylinder chamber 2, provided in the piston 3 is a nozzle 16, throughwhich air can flow in to relieve the negative pressure in the chamberpart 2′. This has the effect that the piston 3 can move on and bepressed into the end position shown in FIG. 3.

[0052] Once the system has been relieved of its load, for example whenthe furniture door or the drawer is opened, the spring 15 pushes thepiston 3, via the piston rod 4, back into the ready position shown inFIG. 1.

[0053] As a variant on the channel 16, there may be provided in thecylinder wall as shown in FIG. 4 a depression 18 which connects the twochamber parts 2′ and 2″, in which case the relief of the negativepressure may be controlled in a manner dependent on the travel of thepiston 3, by differing cross-sections in the depression 18.

[0054] With the damping means according to the invention, doubling thevolume of the chamber part 2′ reduces the air pressure by a factor of0.5. Consequently, only a very small piston travel is necessary, and theimpeding action of the damping means begins very rapidly and increasesvery rapidly to the maximum value. The maximum impeding force is,however, limited by the negative pressure possible in the chamber part2′. The chamber part 2″ is neutral during the damping procedure.

[0055] In the example embodiment according to FIGS. 5 to 10, the piston3 divides the cylinder chamber 2 into a rear negative-pressure chamber2′ and a front pressurised chamber 2″.

[0056] Here too, constructed on the piston 3 is a piston rod 4 whichprojects through a channel 5 in the cylinder 1 and is part of the piston3. The piston rod 4 is received in the channel 5 with play, with theresult that the piston rod 4 and the channel wall 9 delimit an annulargap 10 in the rest position of the piston 3.

[0057] The piston 3 is guided in the cylinder chamber 2 in sealingmanner.

[0058] As in the example embodiment described previously, the piston rod4 comprises two rigid portions 7, 8 between which a resilientlydeformable piston part 6 is arranged. The piston part 6 is constructedas a solid body from material with a rubber-like resilience.

[0059] During damping, the furniture part, for example a door or adrawer, strikes against the buffer 11 of the piston rod 4 and pressesthe latter, together with the piston 3, to the right (in relation to thefigures in the drawing). As soon as the piston 3 moves, a negativepressure is produced behind the piston 3 in the rear negative-pressurechamber 2′ of the cylinder chamber 2, even though air flows in throughthe through openings 13 and the annular gap 10 between the piston rod 4and the wall 9 of the channel 5 into the negative-pressure chamber 2′.Because this annular gap 10 is kept very narrow, the supply of air isvery small.

[0060] During this piston movement, the sealing ring 20 abuts againstthe disc 21 in sealing manner and closes the groove 22, which forms partof the overflow channel. The pressurised chamber 2″ and thenegative-pressure chamber 2′ are therefore separated. The sealing ring20 is constructed in the manner of a piston sealing ring.

[0061] With a relatively fast piston movement, so little air flowsthrough the annular gap 10 into the negative-pressure chamber 2′ that anegative pressure is produced behind the piston 3. This negativepressure generates a force which counteracts the piston movement. Thisnegative pressure is produced very rapidly, but can reach at most 1 bar(and that only in theory). However, it ensures that there is sudden andeffective impeding of the furniture part.

[0062] The negative pressure furthermore has the effect that theresiliently deformable piston part 6 of the piston rod 4 is compressed,whereupon this piston part 6 expands radially and is pressed against thewall 9 of the channel 5. This means the annular gap 10 is closed andfurther movement of the piston 3 is impeded both by the negativepressure in the negative-pressure chamber 2′ and by the friction betweenthe middle piston part 6 and the wall 9.

[0063] At the same time, a pressure is built up in the pressurisedchamber 2″. This takes place more slowly than the build-up of negativepressure in the negative-pressure chamber 2′, but the forces which maybe reached are larger.

[0064] If the piston 3 is moved forward slowly, the sealing ring 20 israised slightly away from the disc 21 and enables air to emerge slowlyfrom the pressurised chamber″. Once the system has been relieved of itsload, for example when the furniture door or the drawer is opened, thespring 15 pushes the piston 3, via the piston rod 4, back into the readyposition shown in FIG. 5. During this, the sealing ring 20 is raisedmarkedly away from the groove 22, with the result that air can come inthrough the groove 22 in the disc 21 and the groove 24 in the piston 3and finally through the slot 25 in the disc 23 into the cylinder space2′.

[0065] In the example embodiment according to FIG. 11, the piston 30 ofthe pressurised chamber 2″ and the piston 31 of the negative-pressurechamber 2′ have different diameters. The pressurised chamber 2″ isarranged in a stepped-down cylinder portion.

[0066] Between the negative-pressure chamber 2′ and the pressurisedchamber 2″ there is a neutral chamber 2′″ which is connected to theexternal air by way of openings 32.

[0067] During damping, that is to say when the piston 30, 31 is movingto the right, negative pressure is again built up in thenegative-pressure chamber 2′ and the piston part 6 is pressed againstthe wall 9 of the channel 5, with the result that on the one hand thenegative-pressure chamber 2′ is sealed off and on the other hand, inaddition to the negative pressure, damping is achieved by frictionbetween the piston part 6 and the wall 9 of the channel 5.

[0068] The overflow point in the piston 30 is the same as in the piston3 in the example embodiment described previously.

[0069] With the damping means according to the invention, doubling thevolume of the negative-pressure chamber 2′ reduces the air pressure by afactor of 0.5. Consequently, only a very small piston travel isnecessary, and the impeding action of the damping means begins veryrapidly and increases very rapidly.

[0070] As a result of the combination of the negative-pressure chamber2′ and the pressurised chamber 2″, the damping begins very rapidly and agood damping profile is obtained.

[0071] To improve the grip between the resiliently deformable pistonpart 6 and the wall 9 of channel 5 during damping, the resilientlydeformable piston part is preferably provided with an uneven surface.Particularly, the cylindrical surface of the resiliently deformablepiston part 6 is provided with ribs 19 which are, in the embodimentshown in FIGS. 12 to 19, annular ribs. The ribs can be rectangular ortriangular in cross section as shown in FIGS. 12 to 16. During dampingthe rigid portions 7, 8 of the piston rod 4 move towards each other asin the former embodiments and the ribs 19 of the resiliently deformablepiston parts 6 are pressed onto the wall 9 of the channel 5.

[0072] In the embodiment shown in FIGS. 20 to 24 the ribs 19 arearranged in axial direction of the piston rod 4.

[0073] In the embodiment shown in FIGS. 25 to 29 the resilientlydeformable piston part 6 is surrounded by a cylindrical sleeve 26. Thematerial of the sleeve 26 is harder and more wear resistant than thematerial of the resiliently deformable piston part 6. The sleeve 26 isprovided with a slot to allow radial extension of the resilientlydeformable piston part 6. The sleeve 26 can be sufficiently stiff inaxial direction to act as an abutment means for the rigid portions 7, 8of the piston rod 4 during damping.

[0074] In the embodiment of FIGS. 30 to 33 the wall 9 of the channel 5is provided with annular ribs 27. When the two rigid portions 7, 8 ofthe piston rod 4 are pushed together and the resiliently deformablepiston part 6 is compressed in axial direction and consequently pressedonto the wall 9 of the channel 5 the ribs 27 penetrate into theresilient material of the piston part 6 and the grip on the piston rod 4is increased.

[0075]FIGS. 14, 18, 22 and 32 show the resiliently formable piston part6 when there is no pressure acting on the piston rod 4. FIGS. 15, 19, 23and 33 show the resiliently deformable piston part 6 during damping.

[0076] In the embodiment of FIGS. 12 to 33 the cylinder 1 is providedwith a valve 28 and a channel 29. On the end of the piston rod 4 opposedto the piston 3 a magnet is provided which makes it possible to easilymove the piston 3 into its ready position after damping.

1. A damping means, in particular for furniture, having a piston whichis linearly displaceable in a cylinder chamber of a cylinder and isprovided with a resiliently deformable piston part which is pressedagainst the cylinder wall during the damping procedure, characterised inthat the resiliently deformable piston part is constructed on a pistonrod, which is constructed on the piston and is guided in a channel inthe cylinder which has a smaller diameter than the piston, with theresiliently deformable piston part widening radially under axialcompressive load and abutting against the wall of the channel.
 2. Adamping means according to claim 1, characterised in that the piston rodand the resiliently deformable piston part are guided in the channelwith play.
 3. A damping means according to claim 1, characterised inthat the resiliently deformable piston part is arranged between twonon-deformable portions of the piston rod.
 4. A damping means accordingto claim 1, characterised in that the resiliently deformable piston partis made as a solid body from material with a rubber-like resilience. 5.A damping means according to claim 1, characterised in that the pistonrod is provided at its free end with a covering cap which has at leastone air through opening.
 6. A damping means according to claim 1,characterised in that the piston, which divides the cylinder chamberinto two chamber parts, is provided with a nozzle which connects the twochamber parts.
 7. A damping means, in particular for furniture, having apiston which is linearly displaceable in a cylinder chamber of acylinder and is provided with a resiliently deformable piston part whichis pressed against the cylinder wall during the damping procedure, inparticular according to claim 1, characterised in that a negativepressure is formed in the cylinder during the damping procedure, betweenthe piston and the resiliently deformable piston part.
 8. A dampingmeans according to claim 7, characterised in that at least one axiallyextending depression is provided in the cylinder wall.
 9. A dampingmeans according to claim 7, characterised by at least one controlledoverflow channel between two chambers at different pressures which arelocated on either side of the piston.
 10. A damping means having acylinder in which at least two pistons are movable and having apressurised chamber and a negative-pressure chamber, in particularaccording to claim 1, characterised in that between the pistons there isprovided a chamber at neutral pressure, and at least one controlledoverflow channel is located between the pressurised chamber and thechamber at neutral pressure.
 11. A damping means according to claim 10,characterised in that the pressurised chamber and the negative-pressurechamber are structurally separated and have different diameters.
 12. Adamping means according to claim 11, characterised in that the diametersof the cylinder and the piston of the negative-pressure chamber arelarger than the diameters of the cylinder and the piston of thepressurised chamber.
 13. A damping means according to claim 10,characterised in that the resilient deformable piston part is arrangedon the opposite side of the piston of the negative-pressure chamber tothat of the piston of the pressurised chamber.
 14. A damping meansaccording to claim 1, characterised in that the resiliently deformablepiston part is provided with an uneven surface.
 15. A damping meansaccording to claim 14, characterised in that the resiliently deformablepiston part is provided with ribs.
 16. A damping means according toclaim 15, characterised in that the resiliently deformable piston partis provided with annular ribs.
 17. A damping means according to claim15, characterised in that at least one of the ribs is provided with atriangular cross section.
 18. A damping means according to claim 15,characterised in that the ribs extend in axial direction of theresiliently deformable piston part.
 19. A damping means according toclaim 1, characterised in that the resiliently deformable piston part issurrounded by a cylindrical sleeve.
 20. A damping means according toclaim 19, characterised in that the cylindrical sleeve is provided witha slot.
 21. A damping means according to claim 19, characterised in thatthe cylindrical sleeve acts as an abutment means between the twonon-deformable portions of the piston rod.
 22. A damping means accordingto claim 19, characterised in that the cylindrical sleeve is made of amaterial which is harder and more wear resistant than the material ofthe resiliently deformable piston part.
 23. A damping means according toclaim 1, characterised in that the wall of the channel is provided withannular ribs.
 24. A damping means according to claim 23, characterisedin that the annular ribs have a saw tooth cross section.